Mathematical models for Enterococcus faecalis recovery after microwave water disinfection

Reznik, Aron; Benjamin, Ellis; Pramanik, Saroj K.; Sowers, Louise; Williams, Arthur L.

doi:10.2166/wh.2009.132

Cited by 3 publications

(3 citation statements)

References 23 publications

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“…pneumophila cells) in each detached sample determined by qPCR, as aforementioned. As a previous study has shown that some bacterial cells injured by disinfection may recover after staying in a disinfectant-free condition for some time, the possible fluctuation of colony counting results with time was tested for L. pneumophila at 0, 1, and 2 days after disinfection (see the SI).…”

Section: Methodsmentioning

confidence: 99%

“…where C culturable L. pneumophila (cfu•mL −1 ) is the concentration of the culturable L. pneumophila in each detached sample determined by colony counting and C total released L. pneumophila (cfu•mL −1 ) is the concentration of the total L. pneumophila (including culturable and nonculturable L. pneumophila cells) in each detached sample determined by qPCR, as aforementioned. As a previous study has shown that some bacterial cells injured by disinfection may recover after staying in a disinfectant-free condition for some time, 36 the possible fluctuation of colony counting results with time was tested for L. pneumophila at 0, 1, and 2 days after disinfection (see the SI).…”

Section: T H Imentioning

confidence: 99%

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Effect of Disinfectant Exposure on Legionella pneumophila Associated with Simulated Drinking Water Biofilms: Release, Inactivation, and Infectivity

Shen

Huang

Lin

et al. 2017

Environ. Sci. Technol.

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Legionella pneumophila, the most commonly identified causative agent in drinking water associated with disease outbreaks, can be harbored by and released from drinking water biofilms. In this study, the release of biofilm-associated L. pneumophila under simulated drinking water flow containing a disinfectant residual was examined. Meanwhile, the inactivation and infectivity (to amoebae) of the released L. pneumophila were studied. To simulate drinking water system conditions, biofilms were prepared under either disinfectant exposure (predisinfected biofilms) or disinfectant-free (untreated biofilms) conditions, respectively. For experiments with water flow containing a disinfectant to release the biofilm-associated L. pneumophila from these two types of biofilms, the L. pneumophila release kinetics values from predisinfected and untreated biofilms under flow condition were not statistically different (one-way ANOVA, p > 0.05). However, inactivation of the L. pneumophila released from predisinfected biofilms was 1-2 times higher and amoeba infectivity was 2-29 times lower than that from untreated biofilms. The higher disinfectant resistance of L. pneumophila released from untreated biofilms was presumably influenced by the detachment of a larger amount of biofilm material (determined by 16S rRNA qPCR) surrounding the released L. pneumophila. This study highlights the interaction among disinfectant residual, biofilms, and L. pneumophila, which provides guidelines to assess and control pathogen risk.

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Section: Methodsmentioning

confidence: 99%

Section: T H Imentioning

confidence: 99%

Effect of Disinfectant Exposure on Legionella pneumophila Associated with Simulated Drinking Water Biofilms: Release, Inactivation, and Infectivity

Shen

Huang

Lin

et al. 2017

Environ. Sci. Technol.

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“…Benjamin et al 24 studied the effect of microwaves on the inactivation of Enterococcus faecalis, Staphylococcus aureus and Escherichia coli present in 100 mL of sterile physiological water. At a power of 130 W, a declumping effect was observed after two minutes for the three species, then a regression of the number of bacteria was observed, and a total inactivation was obtained after 5 min of treatment for Enterococcus faecalis ATCC 29212 and 4 min for Staphylococcus aureus and E. coli.…”

Section: Microwave Effectmentioning

confidence: 99%

Inactivation of E. faecalis under microwave heat treatment and ultrasound probe

Kernou

Belbahi

Bedjaoui

et al. 2023

Nor. Afr. J. Food Nutr. Res.

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Background and aims: The Weibull model was fitted to survival curves in order to describe inactivation kinetics, and the effect of combined microwave (MW) and ultrasound (US) treatments was evaluated. Methods: Enterococcus faecalis ATCC 29212 present in 40 mL of sterile physiological water was treated with microwaves at 300W, 600W, and 900W and/or ultrasonic probes (amplitude 60 %, 80 % and 100 %, pulse (3s continuous, 3s discontinuous). Results: The use of an ultrasonic probe at 20 kHz displayed no significant impact on the patients' ability to survive. At 600 W and 300 W of MW treatment, a decrease of 3.96 log and 0.90 log, respectively, was obtained. Total destruction was accomplished in 70 seconds when 900 W of microwave therapy was used. Additionally, it was shown that the effectiveness of WM and US increased with increasing power and exposure duration. This was the case even when microwave or ultrasonic technology was utilized independently. In addition, the treatment that included both microwaves and ultrasound showed a significantly better effect than the treatment that only involved microwaves, but there were no significant differences between the coupled treatment and the microwave treatment given for 30 seconds. Conclusions: The results of the current study show that the inactivation of Enterococcus faecalis by ultrasound followed by microwave treatment was significantly higher than that obtained by microwave treatment followed by ultrasound. Keywords: Enterococcus faecalis, ultrasound, microwave, inactivation.

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Modeling the Effect of Tylosin Phosphate on Macrolide-Resistant Enterococci in Feedlots and Reducing Resistance Transmission

Stapleton

Cazer

Gröhn

2021

Foodborne Pathogens and Disease

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Tylosin phosphate (TYL) is administered to more than 50% of U.S. beef cattle to reduce the incidence of liver abscesses but may increase the risk of macrolide-lincosamide-streptogramin-resistant bacteria disseminating from the feedlot. Limited evidence has been collected to understand how TYL affects the proportion of resistant bacteria in cattle or the feedlot environment. We created a mathematical model to investigate the effects of TYL administration on Enterococcus dynamics and examined preharvest strategies to mitigate the impact of TYL administration on resistance. The model simulated the physiological pharmacokinetics of orally administered TYL and estimated the pharmacodynamic effects of TYL on populations of resistant and susceptible Enterococcus within the cattle large intestine, feedlot pen, water trough, and feed bunk. The model parameters' population distributions were based on the available literature; 1000 Monte Carlo simulations were performed to estimate the likely distribution of outcomes. At the end of the simulated treatment period, the median estimated proportion of macrolide-resistant enterococci was only 1 percentage point higher within treated cattle compared with cattle not fed TYL, in part because the TYL concentrations in the large intestine were substantially lower than the enterococci minimum inhibitory concentrations. However, 25% of the simulated cattle had a >10 percentage point increase in the proportion of resistant enterococci associated with TYL administration, termed the TYL effect. The model predicts withdrawing TYL treatment and moving cattle to an antimicrobial-free terminal pen with a low prevalence of resistant environmental enterococci for as few as 6 days could reduce the TYL effect by up to 14 percentage points. Additional investigation of the importance of this subset of cattle to the overall risk of resistance transmission from feedlots will aid in the interpretation and implementation of resistance mitigation strategies.

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Mathematical models for Enterococcus faecalis recovery after microwave water disinfection

Cited by 3 publications

References 23 publications

Effect of Disinfectant Exposure on Legionella pneumophila Associated with Simulated Drinking Water Biofilms: Release, Inactivation, and Infectivity

Effect of Disinfectant Exposure on Legionella pneumophila Associated with Simulated Drinking Water Biofilms: Release, Inactivation, and Infectivity

Inactivation of E. faecalis under microwave heat treatment and ultrasound probe

Modeling the Effect of Tylosin Phosphate on Macrolide-Resistant Enterococci in Feedlots and Reducing Resistance Transmission

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